RetouchPRO

Go Back   RetouchPRO > Technique > Photo Retouching
Register Blogs FAQ Site Nav Search Today's Posts Mark Forums Read


Photo Retouching "Improving" photos, post-production, correction, etc.

ICC false profiles for color grading/correction

Reply
 
Thread Tools
  #51  
Old 02-12-2017, 11:18 AM
Shoku Shoku is offline
Senior Member
 
Join Date: Apr 2010
Posts: 296
Re: ICC false profiles for color grading/correctio

Quote:
Originally Posted by Tony W View Post
Different strokes for different folks I guess but I would not bother adjusting the profile gamma but may use the Exposure tab to affect gamma only.
I agree the Exposure adjustment is quick and easily repeatable with Presets. Good Idea.

A similar loss of data. This may not be that debilitating, but it does show a difference compared to Assign Profile which shows no loss of data.

Sample 1 the amount of exposure correction
Sample 2 Levels after Correction
Attached Images
File Type: png exposure.PNG (223.9 KB, 9 views)
File Type: png Levels after Exposure Correction.PNG (187.5 KB, 9 views)
Reply With Quote top
  #52  
Old 02-12-2017, 11:31 AM
andrewrodney's Avatar
andrewrodney andrewrodney is offline
Senior Member
 
Join Date: May 2010
Location: Santa Fe
Posts: 1,079
Re: ICC false profiles for color grading/correctio

Quote:
Originally Posted by Shoku View Post
A similar loss of data. This may not be that debilitating, but it does show a difference compared to Assign Profile which shows no loss of data.

Sample 1 the amount of exposure correction
Sample 2 Levels after Correction
There WILL be data loss with the assign profile hack! Again for the 3rd time, there's no free lunch here! You either alter the numeric values or you don't and when you assign a new profile, then you convert to any other color space, that edit is applied going from source to Lab to output color space.
Reply With Quote top
  #53  
Old 02-12-2017, 11:44 AM
andrewrodney's Avatar
andrewrodney andrewrodney is offline
Senior Member
 
Join Date: May 2010
Location: Santa Fe
Posts: 1,079
Re: ICC false profiles for color grading/correctio

BTW, the same data loss and a bit of a lie about the Histogram takes place with layers. Here's a JPEG with a Gamma adjustment applied as an Adjustment layer and the Histogram from Levels:
http://digitaldog.net/files/GammaHistoLayer.jpg

Smooth as a baby's behind (so no data loss? No!).
Now we flatten this layer and the resulting Histogram from Levels:
http://digitaldog.net/files/GammaHistoFlatt.jpg

Not as smooth. No free lunch. At some point, the layer HAS to be applied to the underlying data. It will happen if you print it, it will happen if you convert it to another color space. It doesn't happen if and only if you view the layered doc in Photoshop. Otherwise, the RGB numbers MUST be changed or you didn't EDIT the image! There is no free lunch. Expect when you don't edit the numbers. OR you do so in high bit where the rounding errors are moot.
Attached Images
File Type: jpg GammaHistoLayer.jpg (57.5 KB, 5 views)
File Type: jpg GammaHistoFlatt.jpg (55.8 KB, 6 views)
Reply With Quote top
  #54  
Old 02-12-2017, 12:43 PM
Tony W's Avatar
Tony W Tony W is offline
Senior Member
Patron
 
Join Date: Mar 2010
Posts: 1,394
Re: ICC false profiles for color grading/correctio

Quote:
Originally Posted by Shoku View Post
We do that, almost every day. With an average of 600 clients a week, and fast turn-around times (one day in some cases), there is often not enough time for the client to re-submit their files. And to complicate the issue of bad files, most of those who submit files that need this type of correction know nothing about Color Management or Monitor Calibration, and it's not always that easy to teach someone over the phone or via email who is clueless, and frankly, just not that interested. A common response: "You're the experts, you fix it."
I now understand where you are coming from.
Quote:
We do not guess or apply crap corrections. We are an offset printing facility. Two offset Komori presses on one HP Digital Press. We correct files for clients, but the majority of our corrections are to prepare files to print based on client instructions or to match submitted printed samples. When the printed sample is lighter or darker than the file we immediately notify the client and proceed based on knowledge, not assumption.
Perhaps crap too harsh a word and certainly not intended to be offensive to you. I was thinking about if I would do the same way and if I did I would not be at all comfortable but our client bases and needs probably quite different and I will have much more time available to help with client education - although there always will be exceptions to the rule
Reply With Quote top
  #55  
Old 02-12-2017, 12:56 PM
Tony W's Avatar
Tony W Tony W is offline
Senior Member
Patron
 
Join Date: Mar 2010
Posts: 1,394
Re: ICC false profiles for color grading/correctio

Quote:
Originally Posted by andrewrodney View Post
...Not as smooth. No free lunch. At some point, the layer HAS to be applied to the underlying data. It will happen if you print it, it will happen if you convert it to another color space. It doesn't happen if and only if you view the layered doc in Photoshop. Otherwise, the RGB numbers MUST be changed or you didn't EDIT the image! There is no free lunch. Expect when you don't edit the numbers. OR you do so in high bit where the rounding errors are moot.
Yes, that's why I was a little careful with choosing the words and suggesting 'just as much damage' referring to exposure/gamma layer or direct adjustment vs assign wrong profile.

My thinking is that if you change the image by whatever method then you must arguably "damage" the image data in the process. Hopefully this "damage" is positive damage (oh I think I have an oxymoron here).

What I do not have is any data to suggest if one method causes more harm than another. And as you say working in high bit as is the case for me most of the time may make the argument irrelevant
Reply With Quote top
  #56  
Old 02-12-2017, 01:26 PM
andrewrodney's Avatar
andrewrodney andrewrodney is offline
Senior Member
 
Join Date: May 2010
Location: Santa Fe
Posts: 1,079
Re: ICC false profiles for color grading/correctio

Agreed on all points Tony. And it would be rather difficult to really figure out which edit was more or less 'damaging' due to many factors (including image content, color space, gamma encoding etc). And most agree, in high bit, it's not worth considering. The image either needs the numbers adjusted or it doesn't. There's no magic here with respect to the 'so called' (no bearing on the president or his comments on judges) False Profile. This isn't anything that can't be done with other tools and it's no better, probably no worse but certainly nothing special.
Reply With Quote top
  #57  
Old 02-12-2017, 03:00 PM
Shoku Shoku is offline
Senior Member
 
Join Date: Apr 2010
Posts: 296
Re: ICC false profiles for color grading/correctio

Quote:
Originally Posted by Tony W View Post
I now understand where you are coming from.
Perhaps crap too harsh a word and certainly not intended to be offensive to you. I was thinking about if I would do the same way and if I did I would not be at all comfortable but our client bases and needs probably quite different and I will have much more time available to help with client education - although there always will be exceptions to the rule
Here are some examples of the edits we are asked to do:
http://www.modernpostcard.com/sites/...ng/gallery.php
Reply With Quote top
  #58  
Old 02-13-2017, 06:03 AM
Tony W's Avatar
Tony W Tony W is offline
Senior Member
Patron
 
Join Date: Mar 2010
Posts: 1,394
Re: ICC false profiles for color grading/correctio

Nice jobs Shoku
Reply With Quote top
  #59  
Old 02-13-2017, 02:50 PM
klev klev is offline
Senior Member
 
Join Date: Jun 2010
Posts: 1,109
Re: ICC false profiles for color grading/correctio

Quote:
Originally Posted by Shoku View Post
Here are some examples of the edits we are asked to do:
http://www.modernpostcard.com/sites/...ng/gallery.php
Those are very nice, especially considering the time/budget constraints that you often describe.
Reply With Quote top
  #60  
Old 02-17-2017, 04:42 PM
marameo's Avatar
marameo marameo is offline
Senior Member
 
Join Date: Oct 2014
Location: The Eternal City
Posts: 155
Re: ICC false profiles for color grading/correctio

Quote:
Originally Posted by klev View Post
It still doesn't show up, and I can't load a cube in Lab mode for obvious reasons. Converting to lab would simply delete that cube. I mean converting to lab would either flatten the image or discard the color lookup layer. I don't think this is a supported workflow in photoshop or at least not CS6. Even in Lab mode, it didn't show up under my export menu.
I see. I think the only way would be to apply that lut on a look up layer adjustment on this color checker image (Adobe RGB) and return it so that I can read the lab values and see what it's all about..

Thanks
Reply With Quote top
Reply

  RetouchPRO > Technique > Photo Retouching


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
where are icc. profiles stored on mac OS 10.8.3? Caravaggio Photo Retouching 10 05-05-2013 10:42 AM
Custom DNG Profiles MikeyPee Software 0 11-20-2011 02:08 PM
NEC SpectraView and ICC profiles shizam1 Hardware 2 04-05-2011 10:09 AM
Installing Ilford icc profiles on a Mac Ken Fournelle Image Help 2 07-31-2004 11:20 AM
new custom ICC profiles black and white, color christophe Input/Output/Workflow 5 05-26-2004 08:26 PM


All times are GMT -6. The time now is 08:10 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
SEO by vBSEO ©2011, Crawlability, Inc.
Copyright © 2016 Doug Nelson. All Rights Reserved